Residual Ionic Liquid Research Articles

Ionic-liquid-tolerant enzymes from an adapted Bacillus paralicheniformis for one-pot conversion of lignocellulosic substrates to ethanol

A newly isolated thermophilic cellulase-producing Bacillus paralicheniformis was subjected to adaptive laboratory evolution in the presence of increasing concentration (from 1 to 5% w w−1) of an otherwise toxic ionic liquid (either 1-ethyl-3-methylimidazolium chloride, or 1-butyl-3-methylimidazolium chloride) over 200-days to obtain strains that produced ionic-liquid-stable enzymes. The ability of the ionic-liquid-adapted strains to grow and produce cellulose hydrolyzing enzymes was proven using several different untreated agroindustrial lignocellulosic substrates. The cellulase of the adapted isolate retained more than 99% of its initial activity after incubation (12 h, ∼25 °C) with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]; 50% w w−1 concentration of ionic liquid). In contrast, the wildtype cellulase retained < 9% of its initial activity after an equivalent exposure to a lesser concentration (15% w w−1) of the ionic liquid. Using untreated sugarcane bagasse as the substrate, the optimal conditions for producing the ionic-liquid-stable enzymes (cellulase, xylanase, β-glucosidase) by the adapted bacterium were 48 °C and an initial pH ∼6. The ionic-liquid-adapted crude enzymes were used in a one-pot process (at 50 °C, 48 h) to release glucose from the ionic-liquid-pretreated wheat straw (pretreatment at 90 °C, 1 h, using 10% (w w−1) wheat straw in [Emim][Ac]), in the presence of the residual ionic liquid. At 48 h of enzymolysis, the glucose concentration exceeded 50 g L−1. This glucose mixed with the residual ionic liquid was fermented (24 h, 37 °C) to ethanol using the conventional yeast Saccharomyces cerevisiae. The ethanol yield on glucose was nearly 56% of the theoretical maximum, despite the yeast not having been adapted to withstand the toxic ionic liquid.

Tailoring ion dynamics in energy storage conductors for ultra-stable, high-performance solid-state microsupercapacitor array

All-solid-state electrochemical energy storage (EES) devices with prolonged lifetime, operational stability, and mechanical flexibility can be a promising route to powering up wearable electronics. However, conventional EES devices have been often hindered by a gradual decrease in energy capacity due to low ionic conducting electrolytes, non-suitable electrode materials, or poor electrode/electrolyte interfaces. Herein, we propose a harmonization of the molecular-level tailoring of ionic gel polymer electrolyte (IGPE) and graphene-based electrodes, significantly improving and sustaining the electrochemical performance (11.9 μWh cm−2) of EES microsupercapacitor (MSC) devices. Our optimized MSC device based on ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI) and interdigitated reduced-graphene oxide (rGO) electrode array maintains 99 % of the initial electrochemical capacity even after 20,000 cycles, also demonstrating the excellent mechanical flexibility (bending radius up to 4 mm) and environmental stability (>30 days) of the MSC-based array. Molecular-level simulation and spectroscopic atomic analysis revealed noticeably lower residual ionic liquid (IL) molecules of EMIM-FSI, compared to EMIM-trifluoromethyl FSI, between the graphene-based layers of electrodes during the charge/discharge cycles. Therefore, our optimization strategy and findings will pave the way to accomplish next-generation of all-solid-state EES devices with ultra-high operational stability, powering wearable electronics.

Understanding the conformational change and inhibition of hyperthermophilic GH10 xylanase in ionic liquid

Xylan is an abundant hemicellulosic feedstock of pentose sugars present in the Lignocellulose biomass, offering massive potential for the generation of biofuel and numerous value-added by-products. The extraction of xylan is a major challenge due to the typical organization of cellulose, hemicellulose and lignin. Ionic Liquid (IL) is a promising solvent for the deconstruction of the complex lignocellulosic structure. However, the residual IL present in the pretreated xylan significantly affects xylanase activity during the hydrolysis. Thus, a molecular understanding focusing on the IL-xylanase interaction needs to be explored for developing IL tolerant xylanases for efficient xylan hydrolysis. In this study, atomistic molecular dynamics (MD) simulations were performed to investigate the IL tolerance of hyperthermophilic GH10B xylanase from Thermotoga maritima (TmXYN10B) in both aqueous and water/1-Ethyl-3-methylimidazolium acetate (EmimAc) binary solvent systems. The enzyme was stable in all solvents at high temperature (363 K). However, the opening and closing motions of the xylanase were lost in high EmimAc concentration. Besides, the formation of a considerable number of hydrogen bonds between acetate anion and amino acids at the enzyme surface might change its native motion in high EmimAc system. The IL induced conformational change was charecterized by constructing Protein Structure Network (PSN) on each snapshot from the MD simulation trajectory. Here we captured the enzyme conformational change by identifying disjoint cliques and communities at the active site in high EmimAc concentration. Furthermore, Emim cations populated the active site with higher binding occupancy and suggested to inhibit the enzymatic hydrolysis. Finally, this study provides a theoretical understanding of the reduced activity of the TmXYN10B xylanase in IL, which can pave the path for engineering xylanases for biofuel production.

Tantalum Oxide Nanoparticles Prepared from Imidazolium Ionic Liquids as Active Hybrid Materials for Enhanced Photocatalytic Degradation of Dyes

AbstractTantalum oxide nanoparticles prepared from the hydrolysis of 1‐alkyl‐3‐methylimidazolium hexachlorotantalate ionic liquids showed an unprecedented efficiency for the photocatalytic degradation of methylene blue and methyl orange dyes in aqueous solutions. Indeed, the photodegradation of these aqueous dyes (up to 94 %) promoted by the Ta2O5 nanoparticles occurred in shorter reaction times when compared to commercially available Ta2O5 under the same reaction conditions. Moreover, the presence of residual ionic liquid and the pH of the medium seem to play significant roles in the photodegradation process. In particular, a significant synergistic effect occurred when the remaining ionic liquid and HCl are present at the surface of the hybrid nanoparticles. This effect provided favorable hydrophilic regions and pH conditions for the photodegradation of the dyes.

Design, synthesis, characterization, and physical property determination of a new ionic liquid: the preparation of triazolo-pyrimidines at room temperature under metal-free conditions

A new ionic liquid is synthesized, and its chemical structure is characterized by FTIR, 1D NMR and 2D NMR, and mass analyses. The thermal behavior and thermal stability of this ionic liquid are investigated. The results approved the formation of 4,4ʹ-trimethylene-N,Nʹ-dipiperidinium sulfate instead of 4,4ʹ-trimethylene-N,Nʹ-dipiperidinium hydrogen sulfate. Moreover, the synthesis of triazolo-pyrimidine derivatives was successfully conducted in the presence of new ionic liquid at room temperature under metal-free conditions, which demonstrated the catalytic efficiency of this ionic liquid. The workup was carried out without the utilization of high-cost column chromatography. After extraction of desired products, the residual ionic liquid could be recycled and reused in the next runs. New ionic liquid exhibited high catalytic activity even after fifth run with no significant change in the chemical structure.

Response of Pseudomonas putida to Complex, Aromatic-Rich Fractions from Biomass.

There is strong interest in the valorization of lignin to produce valuable products; however, its structural complexity has been a conversion bottleneck. Chemical pretreatment liberates lignin-derived soluble fractions that may be upgraded by bioconversion. Cholinium ionic liquid pretreatment of sorghum produced soluble, aromatic-rich fractions that were converted by Pseudomonas putida (P. putida), a promising host for aromatic bioconversion. Growth studies and mutational analysis demonstrated that P. putida growth on these fractions was dependent on aromatic monomers but unknown factors also contributed. Proteomic and metabolomic analyses indicated that these unknown factors were amino acids and residual ionic liquid; the oligomeric aromatic fraction derived from lignin was not converted. A cholinium catabolic pathway was identified, and the deletion of the pathway stopped the ability of P. putida to grow on cholinium ionic liquid. This work demonstrates that aromatic-rich fractions obtained through pretreatment contain multiple substrates; conversion strategies should account for this complexity.

Surface chemistry and electrochemistry of an ionic liquid and lithium on Li4Ti5O12(111)-A model study of the anode|electrolyte interface.

Aiming at a detailed molecular understanding of the initial stage of the solid|electrolyte interphase (SEI) formation in Li-ion batteries, we have investigated the interaction of the battery-relevant ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][TFSI]) (solvent/electrolyte) and Li (Li+ ion shuttle) on well-defined Li-poor Li4Ti5O12(111) and Li-rich Li4.3Ti5O12(111) surfaces/electrodes in a combined surface science and electrochemical model study. X-ray photoelectron spectroscopy (XPS) measurements reveal that postdeposition of Li0 under ultrahigh vacuum (UHV) conditions on a Li-poor Li4Ti5O12(111) surface precovered with a molecularly adsorbed [BMP][TFSI] adlayer leads to little IL decomposition at 80 and 300 K. We assume that most of the Li diffuses through the IL adlayer and rapidly inserts into the Li4Ti5O12(111) bulk. More pronounced IL decomposition was obtained upon IL deposition on a Li-rich Li4.3Ti5O12 phase at 80 K and subsequent heating to 300 K. Cyclic voltammograms (CVs) recorded on the Li4Ti5O12(111) electrodes in Li-TFSI/[BMP][TFSI] indicate an almost reversible Li (de-)insertion, with a slight decay of the amount of (de-)inserted Li with increasing cycle number. XPS measurements performed on the electrode after potential cycling show low intensity signals of IL decomposition products, in addition to dominant signals from residual IL electrolyte, which are related to reaction of the adsorbed IL with Li inserted into/extracted from Li4Ti5O12 during the CV. The results indicate a close similarity between IL decomposition products formed under UHV and under electrochemical conditions, underlining the validity of this experimental approach and the potential of such kind of model studies for obtaining detailed understanding of the SEI formation.

Ionic liquid assisted synthesis of snowflake ZnO for detection of NOx and sensing mechanism

Ionic liquid [Bmim][BF4] is used as a templating agent to synthesize ZnO with snowflake morphology by hydrothermal method. Different calcination temperatures make snowflake ZnO retain different content of ionic liquid residual which results in different gas response. The mesoporous ZnO material obtained after calcination at 650 °C shows the best gas response to NOx. The sensor not only has excellent gas selectivity, but also exhibits an optimal response to NOx (S = 73.4) at 170 °C with a response range of 0.05 ∼ 10 ppm. In addition, the sensor has good repeatability and long-term stability and also exhibits good moisture resistance at different humidity levels which may be attributed to an appropriate amount of residual ionic liquid after high temperature calcination. The reaction mechanism of the sensor to NOx is also discussed in detail based on XPS analysis, GC–MS measurement and DFT calculations.

Ultrasound assisted crystallization of a new cardioactive prototype using ionic liquid as solvent

This work deals with the antisolvent crystallization of LASSBio-294 (3,4-methylenedioxybenzoyl-2-thienylhydrazon) assisted by ultrasound. An ionic liquid (IL), 1-ethyl-3-methylimidazolium methyl phosphonate [emim][CH3O(H)PO2] was used as solvent and water as antisolvent. The influence of the following parameters on crystals properties (size distribution, morphology, residual solvent and in vitro dissolution) were studied with two mixing mode (quick and dropwise) of solution with antisolvent. The impact of washing and drying process was also evaluated. Comparative studies of conventional crystallization conditions (without ultrasound) were also performed. The effect of ultrasound on LASSBio-294 recrystallized properties was influenced by the add mode, water/IL ratio and drug solution concentration. As example, US promoted the formation of small crystals with high residual IL under the following conditions: quick addition, high drug solution concentration and high water/IL ratio. However, despite the decrease of elementary particle size, ultrasound did not avoid crystals agglomeration. The drug dissolution rate was affected by the physical structure of agglomerates. When employed as drying process of washed crystals, spray drying reduced this agglomeration and improved the dissolution of LASSBio-294 crystals.

On the use of benzaldehyde to improve the storage stability of one-pot, epoxy ionic liquid formulations

A series of adducts were prepared based on the reaction of 1-ethyl-3-methylimidazolium acetate and benzaldehyde in various stoichiometries (from equimolar reaction to benzaldehyde in 10-fold excess) and the resulting adducts were characterized using nuclear magnetic resonance spectroscopy (1H, 13C, DEPT, and HQSC experiments). Differential scanning calorimetry was used to examine the initiating behaviour of the adducts towards mono- and di-functional epoxy resins and the data were used to determine kinetic parameters for the polymerization. The lower temperature peak, due to carbene formation, is sensitive to adduct concentration; the residual ionic liquid in the adduct mixture contributes towards the initiation of the curing reaction. When a monofunctional epoxy and the 1:1 adduct was subjected to a 2-week period of storage at room temperature and sub-zero temperatures in the freezer, the profiles of the thermograms for the frozen samples do not change considerably over the storage period and the formulation retains a light yellow colour (rather than the viscous, dark red appearance of the formulation stored at room temperature).

Structural and Morphological Description of Sn/SnOx Core–Shell Nanoparticles Synthesized and Isolated from Ionic Liquid

The potential application of high capacity Sn-based electrode materials for energy storage, particularly in rechargeable batteries, has led to extensive research activities. In this scope, the development of an innovative synthesis route allowing to downsize particles to the nanoscale is of particular interest owing to the ability of such nanomaterial to better accommodate volume changes upon electrochemical reactions. Here, we report on the use of room temperature ionic liquid (i.e., [EMIm+][TFSI-]) as solvent, template, and stabilizer for Sn-based nanoparticles. In such a media, we observed, using Cryo-TEM, that pure Sn nanoparticles can be stabilized. Further washing steps are, however, mandatory to remove residual ionic liquid. It is shown that the washing steps are accompanied by the partial oxidation of the surface, leading to a core-shell structured Sn/SnOx composite. To understand the structural features of such a complex architecture, HRTEM, Mössbauer spectroscopy, and the pair distribution function were employed to reveal a crystallized β-Sn core and a SnO and SnO2 amorphous shell. The proportion of oxidized phases increases with the final washing step with water, which appeared necessary to remove not only salts but also the final surface impurities made of the cationic moieties of the ionic liquid. This work highlights the strong oxidation reactivity of Sn-based nanoparticles, which needs to be taken into account when evaluating their electrochemical properties.

Cellulase Production from Bacillus subtilis SV1 and Its Application Potential for Saccharification of Ionic Liquid Pretreated Pine Needle Biomass under One Pot Consolidated Bioprocess

Pretreatment is the requisite step for the bioconversion of lignocellulosics. Since most of the pretreatment strategies are cost/energy intensive and environmentally hazardous, there is a need for the development of an environment-friendly pretreatment process. An ionic liquid (IL) based pretreatment approach has recently emerged as the most appropriate one as it can be accomplished under ambient process conditions. However, IL-pretreated biomass needs extensive washing prior to enzymatic saccharification as the enzymes may be inhibited by the residual IL. This necessitated the exploration of IL-stable saccharification enzymes (cellulases). Current study aims at optimizing the bioprocess variables viz. carbon/nitrogen sources, medium pH and fermentation time, by using a Design of Experiments approach for achieving enhanced production of ionic liquid tolerant cellulase from a bacterial isolate Bacillus subtilis SV1. The cellulase production was increased by 1.41-fold as compared to that under unoptimized conditions. IL-stable cellulase was employed for saccharification of IL (1-ethyl-3-methylimidazolium methanesulfonate) pretreated pine needle biomass in a newly designed bioprocess named as “one pot consolidated bioprocess” (OPCB), and a saccharification efficiency of 65.9% was obtained. Consolidated bioprocesses, i.e., OPCB, offer numerous techno-economic advantages over conventional multistep processes, and may potentially pave the way for successful biorefining of biomass to biofuel, and other commercial products.

Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts.

Chemical and physical pretreatment of biomass is a critical step in the conversion of lignocellulose to biofuels and bioproducts. Ionic liquid (IL) pretreatment has attracted significant attention due to the unique ability of certain ILs to solubilize some or all components of the plant cell wall. However, these ILs inhibit not only the enzyme activities but also the growth and productivity of microorganisms used in downstream hydrolysis and fermentation processes. While pretreated biomass can be washed to remove residual IL and reduce inhibition, extensive washing is costly and not feasible in large-scale processes. IL-tolerant microorganisms and microbial communities have been discovered from environmental samples and studies begun to elucidate mechanisms of IL tolerance. The discovery of IL tolerance in environmental microbial communities and individual microbes has lead to the proposal of molecular mechanisms of resistance. In this article, we review recent progress on discovering IL-tolerant microorganisms, identifying metabolic pathways and mechanisms of tolerance, and engineering microorganisms for IL tolerance. Research in these areas will yield new approaches to overcome inhibition in lignocellulosic biomass bioconversion processes and increase opportunities for the use of ILs in biomass pretreatment.

이온성 액체를 이용한 바이오매스 추출에 의해 얻어진 추출물의 건조 방법

이온성 액체를 보조용매로 이용할 경우 바이오매스로부터 파클리탁셀의 추출 효율은 획기적으로 개선되지만 잔류이온성 액체로 후속 농축 및 건조에 많은 어려움이 따른다. 따라서 본 연구에서는 공정 효율 향상을 위하여 이온성 액체를 이용한 바이오매스 추출물을 효과적으로 건조할 수 있는 새로운 방법을 개발하였다. 추출물을 물로 전처리하고 추가적으로 세척함으로써 잔류 이온성 액체 제거를 통해 효과적으로 건조할 수 있었다. 물 전처리을 위한 최적의 시료/물 비, 혼합시간 및 추가세척을 위한 최적의 시료/물 비는 각각 1:70 (w/v), 4분, 1:100 (w/v)이었다. 또한 진공 건조보다 마이크로웨이브를 이용한 건조의 경우 건조시간을 9배 정도 단축 가능하여 공정 효율이 획기적으로 개선될 것으로 판단된다.

A novel ionic liquid-tolerant Fusarium oxysporum BN secreting ionic liquid-stable cellulase: Consolidated bioprocessing of pretreated lignocellulose containing residual ionic liquid

In this study, microbial communities from chemicals polluted microhabitats were cultured with the addition of imidazolium-based ionic liquid (IL) to enrich for IL-tolerant microbes. A strain of Fusarium oxysporum BN producing cellulase from these enrichments was capable of growing in 10% (w/v) 1-ethyl-3-methylimidazolium phosphinate, much higher than the normal IL concentrations in the lignocellulose regenerated from ILs. Cellulase secreted by the strain showed high resistance to ILs based on phosphate and sulfate radicals, evidencing of a high conformational stability in relevant media. Gratifyingly, F. oxysporum BN can directly convert IL-pretreated rice straw to bioethanol via consolidated bioprocessing (I-CBP). At optimum fermentation condition, a maximum ethanol yield of 0.125gethanolg−1 of rice straw was finally obtained, corresponding to 64.2% of the theoretical yield.

Yeast tolerance to the ionic liquid 1-ethyl-3-methylimidazolium acetate.

Lignocellulosic plant biomass is the target feedstock for production of second-generation biofuels. Ionic liquid (IL) pretreatment can enhance deconstruction of lignocellulosic biomass into sugars that can be fermented to ethanol. Although biomass is typically washed following IL pretreatment, small quantities of residual IL can inhibit fermentative microorganisms downstream, such as the widely used ethanologenic yeast, Saccharomyces cerevisiae. The aim of this study was to identify yeasts tolerant to the IL 1-ethyl-3-methylimidazolium acetate, one of the top performing ILs known for biomass pretreatment. One hundred and sixty eight strains spanning the Ascomycota and Basidiomycota phyla were selected for screening, with emphasis on yeasts within or closely related to the Saccharomyces genus and those tolerant to saline environments. Based on growth in media containing 1-ethyl-3-methylimidazolium acetate, tolerance to IL levels ranging 1-5% was observed for 80 strains. The effect of 1-ethyl-3-methylimidazolium acetate concentration on maximum cell density and growth rate was quantified to rank tolerance. The most tolerant yeasts included strains from the genera Clavispora, Debaryomyces, Galactomyces, Hyphopichia, Kazachstania, Meyerozyma, Naumovozyma, Wickerhamomyces, Yarrowia, and Zygoascus. These yeasts included species known to degrade plant cell wall polysaccharides and those capable of ethanol fermentation. These yeasts warrant further investigation for use in saccharification and fermentation of IL-pretreated lignocellulosic biomass to ethanol or other products.

Electroless Displacement Deposition of Nanocrystalline Al on Mg Surface from AlCl3-Emic Room Temperature Ionic Liquid

In this paper, electroless displacement deposition of Al on Mg surface in AlCl3-1-ethyl-3-methyl-imidazolium chloride (AlCl3–EMIC) ionic liquid was reported. The electrolytic etching pretreatment of Mg substrate was employed to remove the oxide layers on the surface. The process of displacement deposition was studied by open-circuit potential (OCP) measurement. The electroless deposited Al on Mg was characterized by grazing incidence X-ray diffraction (GIXRD) and scanning electron microscope (SEM). The results showed that for the Mg substrate with oxide layer on the surface, microcrystalline Al crystals of 10-20 μm were obtained in the way of immersing the Mg directly in the ionic liquid. But for the Mg substrate with oxide layer removed, the deposited Al crystals by placing the Mg in the ionic liquid were nanocrystalline, while Al particles of 200-300 nm were deposited by placing the substrate in the glove-box with residual ionic liquid on the surface.

Electroless Displacement Deposition of Nanocrystalline Al on Mg Surface from AlCl3-Emic Room Temperature Ionic Liquid

Introduction Ionic liquids have received considerable attentions recently for their wide use in electrochemistry, synthesis, separation, energy-related applications and so on [1]. As alternative solvents and electrolytes for a number of electrochemical processes, ionic liquids show great advantages comparing with aqueous solution. A range of metal coatings, including water-sensitive metals like Al, Li, Mg, etc, were electrodeposited from ionic liquids [2]. However, the electroless deposition of metals from ionic liquids was rarely reported, except for the deposition of Ag on Cu from a choline chloride-based ionic liquid [3]. Here we report the electroless displacement deposition of Al on Mg from AlCl3-1-ethyl-3-methyl-imidazolium chloride (AlCl3-EMIC) room temperature ionic liquid, especially that nanocrystalline Al can be obtained. Experimental 99.95% Mg substrates used in this study were typically 10×25×1 mm, which were mechanically polished with silicon carbide paper and ultrasonically cleaned with acetone prior to use. An acidic ionic liquid with AlCl3 to EMIC molar ratio of 2:1 was used as the electrolyte. All the experiments referred to AlCl3-EMIC ionic liquid were performed in an argon-filled glove-box at room temperature, in which the oxygen content and moisture were maintained below 1 ppm. To remove the oxide layer on surface, the Mg substrates were firstly electrolytic etched in the 2:1 AlCl3-EMIC ionic liquid at 20 mA/cm2 for 10 min, according to ref. [4-5]. The electroless displacement deposition was carried out by just placing the electrolytic etched Mg plates in the ionic liquid for 20 min or by pulling the etched Mg out of ionic liquid and then placing in the glove-box with the residual ionic liquid on surface for 10 min. The samples after electroless displacement deposition were characterized with X-ray diffraction (XRD) and scanning electron microscope (SEM). Results and discussion XRD pattern of the Mg substrate after deposition is shown in Fig. 1a. The diffraction peaks corresponding to pure Al were clearly detected, which suggests that Al was successfully electroless deposited on Mg surface. The low intensity of Al peaks was due to the low thickness of deposited Al coating. Fig. 1b and Fig. 1c show the SEM micrograph of the deposited Al on Mg. For the sample placed in the ionic liquid (Fig. 1b), the Al crystals can be hardly observed by SEM under the magnification of 50000, while cracks of Al coating can be clearly observed. The deposited Al crystallites should be in the nanometer regime. The cracks of coating might be caused by the high stress in the nanocrystalline Al coating. In the case of placing in the glove-box (Fig. 1c), Al crystals can be clearly observed, which is ca. 200~300 nm. No crack of the coating was observed. Conclusion Al coating was successfully deposited on Mg surface through electroless displacement deposition from AlCl3-EMIC room temperature ionic liquid after an electrolytic etching pretreatment. The results showed that the deposited Al coating was nanocrystalline. Acknowledgment Financial support from National Natural Science Foundation of China (No. 51271166) is gratefully acknowledged.

Investigation of the toxicity of the ionic liquid 1-butyl-3-methylimidazolium chloride to Saccharomyces cerevisiae AY93161 for lignocellulosic ethanol production

Ionic liquid (IL) pretreatment of lignocellulosic materials has provided a new technical tool to improve lignocellulosic ethanol production. To evaluate the influence of the residual IL in the fermentable sugars from enzymatic hydrolysis of IL pretreatment of lignocellulosic materials on the subsequent ethanol fermentation, the toxicity of the IL 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) to Saccharomyces cerevisiae AY93161 was investigated. Firstly, the morphological structure, budding and metabolic activity of Saccharomyces cerevisiae AY93161 at different [BMIM]Cl concentrations were observed under an optical microscope. The results show that its single cell morphology remained unchanged at all [BMIM]Cl concentrations, but its reproduction rate by budding and its metabolic activity decreased with the [BMIM]Cl concentration increasing. The half effective concentration (EC50) and the half inhibition concentration (IC50) of [BMIM]Cl to Saccharomyces cerevisiae AY93161 were then measured using solid and liquid suspension culture and their value were 0.53 and 0.39 g.L-1respectively. Finally, the influence of [BMIM]Cl on ethanol production was investigated. The results indicate that the [BMIM]Cl inhibited the growth and ethanol production of Saccharomyces cerevisiae AY93161. This toxicity study provides useful basic data for further development in lignocellulosic ethanol production by using IL technology and it also enriches the IL toxicity data.

Effects of Solvent Systems on Its Structure, Properties and Electromechanical Behavior of Cellulose Electro-Active Paper

This paper reports a comparative study on the influence of solvent systems on its structure, properties and electromechanical behavior of cellulose electro-active paper. Three types of solvent systems, namely N,N’-dimethylacetamide (DMAc)/LiCl, Trifluoroacetic acid (TFA) and 1-butyl-3-methylimidazolium chloride (BMICL) were studied to dissolve cellulose. Regenerated cellulose from DMAc/LiCl showed the best thermal and tensile properties whereas cellulose regenerated from BMICL exhibited high bending deformation with poor thermal and tensile properties, which might be due to the entrapped residual ionic liquid upon regeneration process. The cellulose regenerated with TFA showed the lowest thermal stability and tensile strength. Details of fabrication and characterization of regenerated cellulose films from three solvent systems are explained. Keywords: Cellulose, DMAc/LiCl, TFA, BMICL, Thermal stability, Mechanical properties, Electromechanical behavior, Cellulose Regeneration, Thermal and Tensile Properties, Electromechanical Behavior